Halo size and subjective complaints of dysphotopsia in a normal population

Abstract

 

Purpose

 

Dysphotopsia is common with multifocal intraocular lenses (MIOLs), with complaints from as many as 45% of those implanted. Some find it severely problematic in day-to-day tasks, such as night driving. Several objective and subjective techniques are available to investigate dysphotopsia, but the relationship between objective and subjective measures is unclear and it is difficult to predict pre-operatively those who might be worst affected subjectively. The aim of this prospective study was to investigate the relationship between objective measures and subjective complaints of dysphotopsia. The normal range of subjective/objective grade (the glare effect ratio) will be determined.

 

Methods

 

Measurements were taken both binocularly and monocularly from 100 healthy participants (mean age: 22 ± 3.21 years; range 18 to 33 years). A bespoke halometer device with glare source was used to quantify the extent of the glare area in 8 meridians. The commercially available C-Quant objectively assessed the amount of straylight falling on the retina using the compensation comparison method. Subjective grading of glare was performed using simulated images from the Photographic Images of Photic Phenomena plates.

 

Results

 

Monocular glare areas (median: 4.25 cm²; range 1.97 to 19.61 cm²) were significantly larger than the binocular glare areas (median: 3.24 cm²; range 1.64 to 8.26 cm²) with the halometer (P < 0.001). There was no relationship between halometer glare area and subjective complaints (r_s = -0.048, r_s² = 0.002, P = 0.635); C-Quant and subjective complaints (r_s = 0.109, r_s² = 0.012, P = 0.279); halometer and C-Quant (r_s = 0.121, r_s² = 0.015, P = 0.231). The normal ranges for the glare effect ratio were 0 - 2.47 (median: 0.87) for halometry, and 0 - 9.41 (median: 3.23) for C-Quant.

 

Conclusions

 

Binocular summation was evident with binocular halos being smaller than monocular halos, suggesting halometry should be performed binocularly. The lack of relationship between subjective and objective measures highlights the difficulty of predicting the potential subjective complaints a patient may experience from an objective measure alone. The normal range of the glare effect ratio could be used for comparison purposes pre- and post- refractive surgery; individuals with the highest ratios may be less suitable for refractive surgery procedures that may induce glare.